<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <script>
        //创建具有初始内容的map
        const map1 = new Map([['a', 1], ['b', 2]])
        const obj = {}

        map1.set(obj, 456);
        map1.set("a", "abc");

        console.log(map1)
        console.log(map1.size)
        console.log("get('a')", map1.get('a'));
        console.log("has('a')", map1.has("a"));
        console.log(map1.delete('b'));
        
    </script>
</body>

</html>